Identification and tracking of tangible objects are essential in a multiplicity of industries. Automatic identification systems are replacing manual identification as automatic systems are more accurate, more efficient and more cost-effective. A key feature of automatic identification systems is remote or contact-less identification. Remote identification improves the accuracy of inventory identification, dramatically reduces the effort required, and allows potentially instant verification of inventory. Typical remote identification systems include Radio Frequency Identification (RFID) technology. Incorporating RFID technology reduces the time, cost and effort for performing identification and tracking when compared to manual methods while significantly improving the accuracy. RFID technology also provides a safer means for identification and tracking both in hazardous environments and identification and tracking of hazardous materials.
In general, a typical RFID systems consists of a transmitter (tag) and a receiver (reader). The tag can be either a passive identification device or an active identification device. A passive tag typically is powered by an external means. One embodiment powers the tag from the reader via a magnetic field generated by the reader. A typical active RFID tag contains its own battery for power. A tag is affixed to an object to be identified. The transmitter sends a radio frequency interrogation signal that activates the tag and the tag emits a signal that identifies the object to which it is attached. The reader could be able to distinguish the identification signals from a single tag or a group of RFID tags. RFID tag readers can be found in two manifestations: hand held readers and fixed readers. The selection of a fixed or handheld reader depends on the application in which it is used.
When designing a handheld reader, there are a multiplicity of factors that need to be taken into account. One of the paramount considerations is that the size, weight, and shape of the reader is manageable by a typical user without excessively compromising the functionality of the reader. A key area for size reduction is the antenna used by a handheld reader. The antenna is used to excite the tag in order to elicit a response that identifies the item to which the tag is attached. Unfortunately, reductions in antenna size also result in reductions in antenna efficiency. Antenna efficiency is a measure of the amount of signal power that an antenna radiates to its environment relative to the amount of power supplied to the antenna. It is desirable to keep antenna efficiency as high as possible as low antenna efficiency requires higher power transmitters and this directly reduces battery life in a handheld reader. Frequently, the antenna size is so small and antenna efficiency is so low that the performance of the handheld reader as measured by its usable range is inadequate for many applications.
For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a hand held RFID reader that provides better performance over existing RFID readers in a variety of environments.